Home-Made 7800 Carts

[Tizoc]

All this talk about Commando has got me thinking about some things. There are many titles for the 7800 that can be hard to find. Unfortunately, a lot of these hard to find titles are some of the better titles for the system.

 

So I pose a question: If there was a place that made carts of these games like Commando, Ikari Wariors, Planet Smashers, etc. Would you guys think that was good? Kinda like a Hozer, but this would be for the 7800.

 

Commando has the Pokey chip, so it will be hard, if not impossible, to build a commando cart. But most of the other titles would be possible. Also, what do you guys think is a fair price for a 7800 cart like this (just plain black cart)?

 

Also, there was been a lack of momentum in the 7800 homebrew scene. Thanks to the CGE guys and HeavenTQA we should have some new 7800 games sometime soon. But this is nothing like the 2600 hombrew scene! So it possible some game authors are holding back on the 7800 because there is really no place to make the 7800 carts? The 2600 Homebrew authors have Hozer to crank out 100 games, but for the 7800 there is no one.

 

So what do the 7800 fans say?

[+-^CrossBow^-]

Do It!

 

I for one really only want an Alien Brigade and Midnight Mutants and some of the other Atari releases that didn't have special chips in them for myself.

 

Assuming the prices weren't outrageous...I would buy!

 

[holygrailvideogames.com]

I wish that there was a 7800 multicart. If one comes out I would buy it.

[Lemmi]

Do it do it do it

 

I would really want Mean 18 golf

[CPUWIZ]

What you really want is one of these ...

 

[cschell]

Keep in mind that many 7800 games require additional bank switching logic and that some require additional RAM inside the cart. I don't recall exactly what the cutoff is at this moment, but it is somewhere around 48K of ROM. Any cartridge whose ROM is larger than that will require additional bank switching logic. And just like the 2600, different companies used different schemes for bank switching. Fortunately, it's not quite as bad as the 2600 because there are fewer schemes and the 7800 cartridge port provides more of the necessary signals to properly implement these schemes, such as the clock and read/write signals from the 6502.

 

I'm not trying to say don't do it, I just wanted to let you know that there are certain complications.

 

Chad

[Atari 7800.com]

Trust me guys... new 7800 game titles are right around the corner. The 7800 is easy to program for once you figure out how to do it.

 

 

Best,

[Lemmi]

Me no want new titles

 

me just wants the ones that are already made to be made again and CHEAPER if possible

[Atari 7800.com]

Me no want new titles  

 

me just wants the ones that are already made to be made again and CHEAPER if possible

 

...cough *pack-in titles* cough... [/i]

[+Mitch]

I think that if O'shea's hadn't raised their prices so much, it would be quite simple to produce Hozer like service for 7800 games. Unfortunately, where as 2600 games can be easily found for $1 or under, plus there are new boards being made for it. The 7800 scene is not so fortunate.

As far as bankswitching stuff goes, if you have one of either of the supercart boards, you can make all but 3 games. (Rampage, F-18, Double Dragon) Also the two Pokey chip games (Ballbalzer, Commando) will lack sound.

 

Mitch

http://atari7800.atari.org

[ubersaurus]

Well, if Sean Kelly gets those new 2600 cart cases up and goin, one could presumably just use those for the 7800 games. Cheaper then going the O' Shea way.

[DanBoris]

This isn't ans big a problem on the 7800 as on the 2600. On the 2600 the bankswitching was done entirely inside the ROM chips, so if you wanted to do your own bankswithcing you had to do it yourself. The 7800 on the other hand used standard ROM chips in all carts, and bankswitching was implemented with standard logic IC's inside the cart. So if you can get a pile of common bankswitched 7800 carts you can just replace the ROM with an EPROM and you have bankswitch cart.

 

Dan

 

Keep in mind that many 7800 games require additional bank switching logic and that some require additional RAM inside the cart.  I don't recall exactly what the cutoff is at this moment, but it is somewhere around 48K of ROM.  Any cartridge whose ROM is larger than that will require additional bank switching logic.  And just like the 2600, different companies used different schemes for bank switching.  Fortunately, it's not quite as bad as the 2600 because there are fewer schemes and the 7800 cartridge port provides more of the necessary signals to properly implement these schemes, such as the clock and read/write signals from the 6502.

 

I'm not trying to say don't do it, I just wanted to let you know that there are certain complications.

 

Chad

[DanBoris]

Part of the reason for the poor 7800 homebrew scene probably has to do with the steep learning curve for the 7800 hardware. The graphics hardware is much different then the 2600 and 7800 and it's isn't real obvious on the first (or second, or third..) read of the tech documents how to use it to produce a game. Also, up until about a year ago there was no way to produce the security key needed for the carts to run, so people probably avoided jumping into homebrewing.

 

Dan

 

Also, there was been a lack of momentum in the 7800 homebrew scene. Thanks to the CGE guys and HeavenTQA we should have some new 7800 games sometime soon. But this is nothing like the 2600 hombrew scene! So it possible some game authors are holding back on the 7800 because there is really no place to make the 7800 carts? The 2600 Homebrew authors have Hozer to crank out 100 games, but for the 7800 there is no one.  

 

So what do the 7800 fans say?

[cschell]

This isn't ans big a problem on the 7800 as on the 2600. On the 2600 the bankswitching was done entirely inside the ROM chips, so if you wanted to do your own bankswithcing you had to do it yourself. The 7800 on the other hand used standard ROM chips in all carts, and bankswitching was implemented with standard logic IC's inside the cart. So if you can get a pile of common bankswitched 7800 carts you can just replace the ROM with an EPROM and you have bankswitch cart.

 

Dan

 

It's not quite that simple. Ask Mitch or Lee about what's involved in converting carts to accept eproms for making Klax. Yes, you can put an eprom on the cart, but it's not a drop in replacement. The pinout of the ROMs does not match the commonly available eproms, so a few traces have to be cut and jumpered.

 

I suppose it is roughly on par with installing the invertor in a 2600 cart though.

 

Chad

[+Mitch]

It's not quite that simple.  Ask Mitch or Lee about what's involved in converting carts to accept eproms for making Klax.  Yes, you can put an eprom on the cart, but it's not a drop in replacement.  The pinout of the ROMs does not match the commonly available eproms, so a few traces have to be cut and jumpered.

 

I suppose it is roughly on par with installing the invertor in a 2600 cart though.

 

Chad

 

True. Though I have recently found a good online source for the 27C100 EPROM. It saves a couple of steps over using a 27C010.

 

Mitch

http://atari7800.atari.org